All my DDs have a different uniform from winter to summer, so it's not a huge issue.
DD1,2 and 3 wear kilt, dark tights, shirt, tie, sleeveless jumper and blazer in winter. In summer they wear a navy skirt, striped blouse with revere collar, socks/tights, sleeveless jumper and blazer. The blazer is used as a coat in summer, and hung up during the day whilst on school grounds.
DD4 wears a kilt, dark tights, shirt, tie, cardigan and blazer in winter, and a summer dress with socks, cardigan and blazer in summer.
I must say though, I'm a bit skeptical about needing to adjust clothes. I work in a profession which requires a dark suit, collared shirt, dark tights and a robe. DH is required to wear a suit and shirt and tie. DH has had to wear this sort of thing in hot countries on business (think Dubai, Saudi, etc.) Neither of us have died yet. If it's a uniform with a shirt, blazer and tie, it's not really much different to what you would wear to work in a lot of professions. Maybe I'm a hard hearted Hannah though!